anywidget

Minor Changes

• Add signal (AbortSignal) to initialize and render props for lifecycle cleanup (#974)

  Both initialize and render now receive an AbortSignal via the signal prop. The signal is aborted when the widget is destroyed (or during HMR). This is the preferred way to manage cleanup going forward — it composes with the broader web platform (addEventListener, fetch, child widgets) and avoids the need to manually track teardown logic.

  The previous callback-based pattern continues to work but is no longer recommended:

  // before
  export default {
    render({ model, el }) {
      let handler = () => { /* ... */ };
      model.on("change:value", handler);
      return () => model.off("change:value", handler);
    },
  };
  
  // after
  export default {
    render({ model, el, signal }) {
      let handler = () => { /* ... */ };
      model.on("change:value", handler);
      signal.addEventListener("abort", () => model.off("change:value", handler));
    },
  };
  

  signal also works with addEventListener and fetch directly:

  export default {
    render({ model, el, signal }) {
      el.addEventListener(
        "click",
        () => {
          /* ... */
        },
        { signal }
      );
    },
  };